Salvaging Station + Clock of Omens + Grinding Station + Phyrexian Metamorph

Salvaging Station

Clock of Omens

Grinding Station

Phyrexian Metamorph

How it works

1. Activate Salvaging Station by tapping it, returning a noncreature artifact with mana value 1 or less from your graveyard to the battlefield.
2. When the artifact enters, Grinding Station and Phyrexian Metamorph trigger, untapping themselves.
3. Activate Clock of Omens by tapping Phyrexian Metamorph and the noncreature artifact returned in step 1, untapping Grinding Station.
4. Activate Grinding Station by tapping it and sacrificing the noncreature artifact, causing a player to mill three cards.
5. Repeat.